Test MP-STXR

AArch64 MP-STXR
{
0:X1=x0; 0:X4=x1; 0:X5=x2;
1:X2=x1; 1:X4=x0;
}
 P0             | P1          ;
 LDR W0,[X1]      | MOV W0,#1   ;
 EOR W2,W0,W0            | MOV W1,#2   ;
 NOP                     | MOV W3,#3   ;
 STR  WZR,[X5,W2,SXTW]   | STR W0,[X2] ;
 LDXR  W9,[X5]           | STR W1,[X2] ;
 STXR W2,W9,[X5]         | DMB SY      ;
 EOR W2,W2,W2            | STR W3,[X4] ;
 LDR W3,[X4,W2,SXTW]     |             ;
Observed
    0:X3=1; 0:X0=3;
and 0:X3=0; 0:X0=3;